CN112338203A

CN112338203A - Powder recycling method, conformal powder supporting structure and design method thereof

Info

Publication number: CN112338203A
Application number: CN202011236150.4A
Authority: CN
Inventors: 王耿; 徐君; 王琳; 石凯凯; 吕彬炜; 赵仲
Original assignee: Zhejiang Tianxiong Industrial Technology Co ltd
Current assignee: Zhejiang Tianxiong Industrial Technology Co ltd
Priority date: 2020-11-09
Filing date: 2020-11-09
Publication date: 2021-02-09
Anticipated expiration: 2040-11-09
Also published as: CN112338203B

Abstract

The invention discloses a powder recycling method, a conformal powder supporting structure and a design method thereof. The conformal powder supporting structure is composed of periodically distributed flat plate and lattice structures, wherein the flat plate structure is used for supporting powder, and the lattice structures are used for supporting the flat plate structure. The conformal powder supporting structure and the parts are printed simultaneously, the powder in the forming cabin can be recycled every time one 'flat plate + dot matrix' period is printed for the next section of printing, the powder is recycled for several times in the printing process, and the powder consumption required by one-time printing can be greatly reduced.

Description

Powder recycling method, conformal powder supporting structure and design method thereof

Technical Field

The invention belongs to the technical field of powder bed melting additive manufacturing, and particularly relates to a powder bed melting forming method with high powder utilization rate.

Background

The powder bed melting technology can realize the precise printing of complex structural parts made of metal and nonmetal materials, and is widely applied to the industries of aviation, aerospace, automobiles, medical treatment and the like. The powder bed melting technique requires that the powder is spread evenly on the working platform for each layer of printing, then the areas are melted according to the given procedure, and the process is repeated until the printing is finished. The mode of spreading and printing layer by layer enables the powder bed melting technology to realize the precise printing of complex structural parts. However, when a part with a high height and a small cross section is printed, since powder needs to be spread over the whole workbench in the printing process, the weight of the powder required for one-time printing is often dozens of times of the weight of the part, and the printing cost of a single product is high.

The invention content is as follows:

the technical problems solved by the invention are as follows: the powder utilization rate of the existing powder bed melting additive manufacturing technology is low.

In order to solve the technical problem, the invention adopts the following scheme: a method for recycling powder is applied to a powder bed fusion forming process, a conformal powder supporting structure is arranged in a forming cabin of a printing forming part, the conformal powder supporting structure comprises one or a plurality of supporting units, and the method for recycling powder comprises the following steps:

step 01: the first supporting unit prints the parts printed in sections at the same time, and printing is suspended after the first supporting unit prints;

step 02: collecting the powder in the forming cabin into a powder supply system, and then paving the powder to continuously print the next supporting unit and the next section of the part;

step 03: and after the next supporting unit and the next section of the part are printed, pausing the printing, repeating the step 02, and repeating the steps till the printing of the part is finished.

The invention uses the conformal powder supporting structure in the non-printing area of the powder bed fusion forming, can realize the recycling of the powder in the part printing process, and particularly reduces the powder consumption of one-time printing aiming at the parts with small sectional area and higher height so as to improve the utilization rate of the powder.

The conformal powder supporting structure in the method for recycling the powder comprises at least one supporting unit, wherein the supporting unit comprises a first structure and a second structure which are connected, the first structure is a flat plate structure, the second structure is a lattice structure, and the second structure supports the first structure, namely the flat plate structure supports the powder. Because the flat plate structure is thin in thickness and the second structure is of a dot matrix structure, the consumable materials of the printing forming supporting unit and the conformal powder supporting structure are few, and the improvement of the powder utilization rate is facilitated. The flat plate structure and the dot matrix structure of the conformal powder supporting structure are periodically distributed along the printing deposition direction in a dot matrix structure-flat plate structure mode.

A design method of a conformal powder supporting structure comprises the following steps:

step 01: placing a part to be printed on a substrate, wherein the other areas except the part are non-printing areas in a forming cabin;

step 02: extracting a non-printing area, and dividing the non-printing area into N parts along the deposition direction of printing, wherein the N parts are 1, … … and N sections in sequence;

step 03: extracting 1, … …, N-1 sections of non-printing areas, dividing each section of non-printing area into a part a and a part b along the deposition direction of printing, wherein the part a generates a flat plate structure, the part b generates a lattice structure, each 1 section of non-printing area forms a supporting unit, and N-1 supporting units are calculated; alternatively, the plate structure is parallel to the substrate, and the thickness is generally less than 1 mm;

step 04: and combining the N-1 support units processed in the step 03 to generate a conformal powder support structure.

The inner contour of the non-printed area extracted in step 02 above conforms to the outer contour of the part. The conformal powder supporting structure used by the invention has certain rigidity, and the conformal powder supporting structure is connected with the outer contour of the part, so that the effect of keeping the outline dimension of the part can be achieved.

Description of the drawings:

FIG. 1: a schematic view of a powder bed fusion molding chamber;

FIG. 2: a schematic diagram of the placement of parts on a substrate;

FIG. 3: a schematic of parts and non-printed areas in the molding chamber;

FIG. 4: a non-printing region segmentation schematic diagram;

FIG. 5: schematic diagrams of conformal powder support structures and parts;

FIG. 6: a schematic of a substrate-supporting powder;

FIG. 7: a schematic view of the first support unit supporting the powder;

FIG. 8: a schematic view of the second support unit supporting the powder; FIGS. 6 to 8 constitute schematic views of the recycling of the powders;

FIG. 9: a powder recycling method and a general flow chart of a conformal powder support structure design method thereof.

The symbols in the drawings illustrate that:

1-forming a cabin;

2-a substrate; 21-outer contour of substrate;

3, parts; 31-part outer contour;

4-non-print area; 41-paragraph 1 non-print area; 42-paragraph 2 non-print region; 43-paragraph 3 non-print region; 44-inner contour of non-printed area;

5, forming a powder supporting structure;

6-powder;

7-deposition direction.

The specific implementation mode is as follows:

the present invention is further described below with reference to FIGS. 1 to 9:

step 01: a component 3 to be printed is placed on the substrate 2. Preferably, the component 3 is placed in the central position of the base plate 2, as shown in fig. 2.

Step 02: the non-print area 4 is generated. The non-printing area 4 is an area in the forming chamber 1 that requires powder coverage in addition to the part 3, as shown in fig. 3.

Step 03: the non-printing area 4 is divided. The non-printed area 4 is divided perpendicularly to the deposition direction 7 of the part 3, dividing the non-printed area 4 into 3 segments, preferably from the 1 st segment 41, the 2 nd segment 42, the 3 rd segment 43, with a decreasing volume, as shown in fig. 4.

Step 04: a conformal powder support structure 5 is created. And extracting a 1 st segment 41 and a 2 nd segment 42 of the non-printing area, dividing each segment into a part a and a part b perpendicular to the part deposition direction 7, wherein the part a has the height within 1mm to generate a flat plate structure, and the part b generates a dot matrix structure. And combining the processed non-printing areas of the 1 st and 2 nd sections to generate a conformal powder supporting structure 5.

Step 05: a print program is generated. The conformal powder support structure 5 generated in step 04 is used in place of the non-printed area 4 of step 02, as shown in fig. 5, and the part and conformal powder support structure are then sliced to generate a print program.

Step 06: the printing program is introduced into the apparatus, printing is started, and after the printing of the 1 st stage 41 is completed, printing is suspended.

Step 07: the powder is recovered and the next printing stage is started. And (4) recovering the powder 6 in the forming cabin into the powder supply system, then spreading the powder again, continuing the 2 nd segment 42 printing, and pausing the printing after the printing is finished.

Step 08: step 07 is cycled until the part is printed as shown in fig. 6-8.

Because the powder 6 can be recycled in the printing process, the whole part 3 is printed only by preparing the powder which can finish the 1 st stage of printing, and the powder consumption is greatly reduced.

The invention is described above with reference to the accompanying drawings, it is obvious that the implementation of the invention is not limited in the above manner, and it is within the scope of the invention to adopt various modifications of the inventive method concept and solution, or to apply the inventive concept and solution directly to other applications without modification.

Claims

1. A method for recycling powder is applied to a powder bed fusion forming process, and is characterized in that: a conformal powder supporting structure (5) is arranged in a forming cabin (1) for printing formed parts, the conformal powder supporting structure comprises one or a plurality of supporting units, and the method for recycling powder comprises the following steps:

step 01: the first supporting unit and the part (3) printed in the subsection mode are printed simultaneously, and printing is suspended after the first supporting unit finishes printing;

step 02: collecting the powder in the forming cabin (1) into a powder supply system, and then paving the powder to continuously print the next supporting unit and the next section of the part;

2. A conformal powder support structure comprising at least one support unit, the support unit comprising a first structure and a second structure connected, wherein: the first structure is a flat plate structure, the second structure is a lattice structure, and the second structure supports the first structure.

3. The conformal powder support structure of claim 2, wherein: the flat structure is parallel to the base plate (2) of the forming cabin.

4. The conformal powder support structure of claim 2 or 3, wherein: all support units are superimposed along a deposition direction (7) of the printing.

5. A design method of a conformal powder supporting structure comprises the following steps:

step 01: placing a part (3) to be printed on a substrate (2), wherein the other area except the part is a non-printing area (4) in a forming cabin (1);

the method is characterized in that: step 02: extracting a non-printing area (4), and dividing the non-printing area into N parts along a deposition direction (7) of printing, wherein the N parts are 1, … … and N sections in sequence;

step 03: extracting 1, … …, N-1 sections of non-printing areas, dividing each section of non-printing area into a first part and a second part along the deposition direction (7) of printing, wherein the first part generates a flat plate structure, the second part generates a lattice structure, and each 1 section of non-printing area forms a supporting unit, and the total number of the supporting units is N-1;

step 04: and combining the N-1 support units processed in the step 03 to generate a conformal powder support structure (5).

6. The method of designing a conformal powder support structure according to claim 5, wherein: in step 02, the volume of the N non-printing areas is gradually reduced along the deposition direction (7) of the printing.

7. The method of designing a conformal powder support structure according to claim 5, wherein: the inner contour of the non-printed area extracted in step 02 conforms to the outer contour (31) of the part.